Redox - Corrosion

In 1763, the British Admirality covered wooden ship HMS Alarm with copper sheeting to protect it from marine worms. This was sucessful but, they reported: '... we were surprised to perceive the effect of the copper had upon iron where the two metals touched... the nails and staples... were found dissolved into a rusty paste.' Briefly explain this occurrence and how it might have been prevented.

This should be easy for you guys...

I know that both the metals undergo wet corrosion, but I don't know anything about the effect on having the two metals in contact.